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authorEric Dumazet <edumazet@google.com>2026-04-21 17:33:49 +0300
committerJakub Kicinski <kuba@kernel.org>2026-04-23 07:12:40 +0300
commita6edf2cd4156b71e07258876b7626692e158f7e8 (patch)
treeb3878e5eb59c9f32f603c894c5f94d970b428343
parent9d146a5d10685ab19e15bbedc5107c5b94d45ebe (diff)
downloadlinux-a6edf2cd4156b71e07258876b7626692e158f7e8.tar.xz
net_sched: sch_hhf: annotate data-races in hhf_dump_stats()
hhf_dump_stats() only runs with RTNL held, reading fields that can be changed in qdisc fast path. Add READ_ONCE()/WRITE_ONCE() annotations. Fixes: edb09eb17ed8 ("net: sched: do not acquire qdisc spinlock in qdisc/class stats dump") Signed-off-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Jamal Hadi Salim <jhs@mojatatu.com> Link: https://patch.msgid.link/20260421143349.4052215-1-edumazet@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
-rw-r--r--net/sched/sch_hhf.c19
1 files changed, 10 insertions, 9 deletions
diff --git a/net/sched/sch_hhf.c b/net/sched/sch_hhf.c
index 95e5d9bfd9c8..96021f52d835 100644
--- a/net/sched/sch_hhf.c
+++ b/net/sched/sch_hhf.c
@@ -198,7 +198,8 @@ static struct hh_flow_state *seek_list(const u32 hash,
return NULL;
list_del(&flow->flowchain);
kfree(flow);
- q->hh_flows_current_cnt--;
+ WRITE_ONCE(q->hh_flows_current_cnt,
+ q->hh_flows_current_cnt - 1);
} else if (flow->hash_id == hash) {
return flow;
}
@@ -226,7 +227,7 @@ static struct hh_flow_state *alloc_new_hh(struct list_head *head,
}
if (q->hh_flows_current_cnt >= q->hh_flows_limit) {
- q->hh_flows_overlimit++;
+ WRITE_ONCE(q->hh_flows_overlimit, q->hh_flows_overlimit + 1);
return NULL;
}
/* Create new entry. */
@@ -234,7 +235,7 @@ static struct hh_flow_state *alloc_new_hh(struct list_head *head,
if (!flow)
return NULL;
- q->hh_flows_current_cnt++;
+ WRITE_ONCE(q->hh_flows_current_cnt, q->hh_flows_current_cnt + 1);
INIT_LIST_HEAD(&flow->flowchain);
list_add_tail(&flow->flowchain, head);
@@ -309,7 +310,7 @@ static enum wdrr_bucket_idx hhf_classify(struct sk_buff *skb, struct Qdisc *sch)
return WDRR_BUCKET_FOR_NON_HH;
flow->hash_id = hash;
flow->hit_timestamp = now;
- q->hh_flows_total_cnt++;
+ WRITE_ONCE(q->hh_flows_total_cnt, q->hh_flows_total_cnt + 1);
/* By returning without updating counters in q->hhf_arrays,
* we implicitly implement "shielding" (see Optimization O1).
@@ -403,7 +404,7 @@ static int hhf_enqueue(struct sk_buff *skb, struct Qdisc *sch,
return NET_XMIT_SUCCESS;
prev_backlog = sch->qstats.backlog;
- q->drop_overlimit++;
+ WRITE_ONCE(q->drop_overlimit, q->drop_overlimit + 1);
/* Return Congestion Notification only if we dropped a packet from this
* bucket.
*/
@@ -686,10 +687,10 @@ static int hhf_dump_stats(struct Qdisc *sch, struct gnet_dump *d)
{
struct hhf_sched_data *q = qdisc_priv(sch);
struct tc_hhf_xstats st = {
- .drop_overlimit = q->drop_overlimit,
- .hh_overlimit = q->hh_flows_overlimit,
- .hh_tot_count = q->hh_flows_total_cnt,
- .hh_cur_count = q->hh_flows_current_cnt,
+ .drop_overlimit = READ_ONCE(q->drop_overlimit),
+ .hh_overlimit = READ_ONCE(q->hh_flows_overlimit),
+ .hh_tot_count = READ_ONCE(q->hh_flows_total_cnt),
+ .hh_cur_count = READ_ONCE(q->hh_flows_current_cnt),
};
return gnet_stats_copy_app(d, &st, sizeof(st));